1. The Field of the Invention
The present invention relates to connectors for joining components in fluid transmission systems, such as exhaust systems for internal combustion engines, wherein the connector will be exposed to axial, transverse and bending vibrations and forces. In particular, the present invention relates to connectors for joining pipes to one another or to other structures in exhaust systems for vehicles.
2. The Prior Art
It is well known that, in vehicle exhaust systems, the internal combustion (i.e., engines) produces significant amounts of vibration in the exhaust system. Operation of the motors at continuous speeds for prolonged periods of time can, especially, produce what are known as harmonic vibrations which can cause significant deflections in extended lengths of exhaust pipe and at locations where such pipes are mounted to structures such as brackets, engine manifolds and the like. Repeated deflections and vibrations along the exhaust pipe system, can, in turn, cause the structures to weaken with time and ultimately fail. Further, such harmonic vibrations can also be transmitted through the exhaust pipes to the mountings of the pipes, promoting the loosening of the mountings which can result in the displacement of one or more components of the exhaust system, with the potential for both personal injury and equipment damage.
In addition to the vibrations caused by the operation of the motor of a vehicle, an exhaust system is also subjected to various tension, compression and bending forces which also arise during the operation of the vehicle. While individual exhaust system components could be made stronger and more massive to resist failure by fatigue, such constructions would be undesirable due to weight considerations. Further, by making individual elements stiffer, the vibrations are merely transmitted throughout the exhaust system to the mountings or other components and are not reduced or eliminated. Accordingly, it is desirable to isolate the exhaust system, or at least components of the system, from such vibration and forces.
It is known that if the pipes of an exhaust system or other components, are divided and separated by non-rigid connections, rather than being constructed as continuous extended lengths and/or rigid connections, the development of harmonic vibrations from the motor is precluded or reduced. Such non-rigid connections can be advantageously employed to absorb other tension, compression and bending forces, apart from and in addition to the motor vibration.
It is therefore desirable to provide a connector for joining a length of exhaust pipe to another pipe or to a mounting, such as an engine manifold, which connector joins the components in a non-rigid fashion and is capable of absorbing tension, compression and bending forces, as well as vibrational forces, without transmitting them from one exhaust system component to another.
One method for providing a connection which is non-rigid and capable of precluding or reducing transmission of vibrations, between an engine component and engine component such as an exhaust manifold, and the pipes of an exhaust system is to provide a ball joint structure at the point of connection of the pipe to the manifold. Typically, such prior art ball joint connections utilize a concave socket structure surrounding the aperture in the exhaust manifold. A fitting is then provided at the end of the exhaust pipe which has a corresponding spherical or ball type configuration so that pivotal movement is enabled between the pipe end and the manifold. In order to attempt to maintain tight contact between the pipe end and the manifold, typically the joint is provided with a preload in the form of a spring or springs or other clamping members which exert a compressive force tending to hold the pipe end spherical portions in relatively tight contact with socket portions of the manifold.
However, the exhaust pipes are often subjected to tension forces which may result from forces exerted to the pipe or to the engine itself which may tend to pull apart the ball and socket portions of the joint. The resulting gap which may occur between the ball and socket portions permits the escape of exhaust gases from the ball joint. In addition, in the ordinary course of operation during which time the joint is continuously subjected to high frequency, low amplitude vibration simply from the operation of the engine, the mere act of pivoting movement by the pipe and relative to the manifold means that a small, but nevertheless finite clearance exists between the ball and socket portions of the connection, likewise permitting the escape of exhaust gases. Typically, such ball and socket joints have not been provided with further means for assuring the prevention of the escape of exhaust gases.
Increasing governmental pollution regulations, however, have placed greater importance on the further reduction of vehicle emissions, including such unintentional exhaust emissions as those described. While some attempts have been made to provide for sealed ball joint connector constructions, such as those illustrated in such references as Hess, U.S. Pat. No. 4,893,847, Doat, U.S. Pat. No. 4,911,482, French Application No. 2 644 552, British Patent No. 1,101,074 and European Patent Application No. EP 0 718 537, such prior art constructions typically are either configured solely for connecting abutting simple cylindrical pipe ends, and are not suitable for direct connection of a pipe to an exhaust manifold, or alternatively have been designed to mate with specific existing manifold structures, and may not be compatible with different kinds of existing exhaust manifolds, or exhaust manifolds the configurations of which have been modified. In addition, such prior art sealed flexible coupling structures are often particularly difficult to install, repair, or otherwise maintain. Accordingly, it would be desirable to provide a flexible connector system for use in fluid transmission systems, such as the exhaust systems of vehicle having internal combustion engines, which is not only capable of precluding the transmission of vibrations from the engine along the exhaust system, but is also capable of providing enhanced protection against the undesired escape of exhaust gases.
It would also be desirable to provide such a sealed flexible connector system for exhaust systems, which is capable of being integrated with existing or only slightly modified manifold structures and configurations, from that of non-sealed systems.
It would be still further desirable to provide such a flexible connector system which is more easily installed and/or maintained.
These and other objects of the present invention will become apparent in light of the present specification including claims and drawings.